Utils

java.lang.Object
- org.omnifaces.util.Utils

```
public final class Utils
extends Object
```
Collection of general utility methods that do not fit in one of the more specific classes.

Author:

Arjan Tijms, Bauke Scholtz

Method Summary

Methods
Modifier and Type	Method and Description
`static IOException`	`close(Closeable resource)` Check if the given resource is not `null` and then close it, whereby any caught `IOException` is been returned instead of thrown, so that the caller can if necessary handle (log) or just ignore it without the need to put another try-catch.
`static <T> T`	`coalesce(T... objects)` Returns the first non-`null` object of the argument list, or `null` if there is no such element.
`static String`	`formatRFC1123(Date date)` Formats the given `Date` to a string in RFC1123 format.
`static boolean`	`isEmpty(Collection<?> collection)` Returns true if the given collection is null or is empty.
`static boolean`	`isEmpty(Object value)` Returns true if the given value is null or is empty.
`static boolean`	`isEmpty(Object[] array)` Returns true if the given array is null or is empty.
`static boolean`	`isEmpty(String string)` Returns true if the given string is null or is empty.
`static <T> boolean`	`isOneOf(T object, T... objects)` Returns `true` if the given object equals one of the given objects.
`static Date`	`parseRFC1123(String string)` Parses the given string in RFC1123 format to a `Date` object.
`static String`	`serializeURLSafe(String string)` Serialize the given string to the short possible unique URL-safe representation.
`static long`	`stream(InputStream input, OutputStream output)` Stream the given input to the given output by NIO `ByteBuffer`.
`static <T> Set<T>`	`unmodifiableSet(Object... values)` Creates an unmodifiable set based on the given values.
`static String`	`unserializeURLSafe(String string)` Unserialize the given serialized URL-safe string.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - isEmpty
```
public static boolean isEmpty(String string)
```
    Returns true if the given string is null or is empty.
    
    Parameters:
    string - The string to be checked on emptiness.
    
    Returns:
    True if the given string is null or is empty.
  - isEmpty
```
public static boolean isEmpty(Object[] array)
```
    Returns true if the given array is null or is empty.
    
    Parameters:
    array - The array to be checked on emptiness.
    
    Returns:
    True if the given array is null or is empty.
  - isEmpty
```
public static boolean isEmpty(Collection<?> collection)
```
    Returns true if the given collection is null or is empty.
    
    Parameters:
    collection - The collection to be checked on emptiness.
    
    Returns:
    True if the given collection is null or is empty.
  - isEmpty
```
public static boolean isEmpty(Object value)
```
    Returns true if the given value is null or is empty. Types of String, Collection, Map and Array are recognized. If none is recognized, then examine the emptiness of the toString() representation instead.
    
    Parameters:
    value - The value to be checked on emptiness.
    
    Returns:
    True if the given value is null or is empty.
  - coalesce
```
public static <T> T coalesce(T... objects)
```
    Returns the first non-null object of the argument list, or null if there is no such element.
    
    Type Parameters:
    T - The generic object type.
    Parameters:
    objects - The argument list of objects to be tested for non-null.
    
    Returns:
    The first non-null object of the argument list, or null if there is no such element.
  - isOneOf
```
public static <T> boolean isOneOf(T object,
                  T... objects)
```
    Returns true if the given object equals one of the given objects.
    
    Type Parameters:
    T - The generic object type.
    Parameters:
    object - The object to be checked if it equals one of the given objects.
    objects - The argument list of objects to be tested for equality.
    
    Returns:
    true if the given object equals one of the given objects.
  - stream
```
public static long stream(InputStream input,
          OutputStream output)
                   throws IOException
```
    Stream the given input to the given output by NIO ByteBuffer. Both the input and output streams will implicitly be closed after streaming, regardless of whether an exception is been thrown or not.
    
    Parameters:
    input - The input stream.
    output - The output stream.
    
    Returns:
    The length of the written bytes.
    
    Throws:
    
    IOException - When an I/O error occurs.
  - close
```
public static IOException close(Closeable resource)
```
    Check if the given resource is not null and then close it, whereby any caught IOException is been returned instead of thrown, so that the caller can if necessary handle (log) or just ignore it without the need to put another try-catch.
    
    Parameters:
    resource - The closeable resource to be closed.
    
    Returns:
    The caught IOException, or null if none is been thrown.
  - unmodifiableSet
```
public static <T> Set<T> unmodifiableSet(Object... values)
```
    Creates an unmodifiable set based on the given values. If one of the values is an instance of an array or a collection, then each of its values will also be merged into the set. Nested arrays or collections will result in a ClassCastException.
    
    Parameters:
    values - The values to create an unmodifiable set for.
    
    Returns:
    An unmodifiable set based on the given values.
    
    Throws:
    
    ClassCastException - When one of the values or one of the arrays or collections is of wrong type.
    Since:
    
    1.1
  - formatRFC1123
```
public static String formatRFC1123(Date date)
```
    Formats the given Date to a string in RFC1123 format. This format is used in HTTP headers and in JavaScript Date constructor.
    
    Parameters:
    date - The Date to be formatted to a string in RFC1123 format.
    
    Returns:
    The formatted string.
    Since:
    
    1.2
  - parseRFC1123
```
public static Date parseRFC1123(String string)
                         throws ParseException
```
    Parses the given string in RFC1123 format to a Date object.
    
    Parameters:
    string - The string in RFC1123 format to be parsed to a Date object.
    
    Returns:
    The parsed Date.
    
    Throws:
    
    ParseException - When the given string is not in RFC1123 format.
    Since:
    
    1.2
  - serializeURLSafe
```
public static String serializeURLSafe(String string)
```
    Serialize the given string to the short possible unique URL-safe representation. The current implementation will decode the given string with UTF-8 and then compress it with ZLIB using "best compression" algorithm and then Base64-encode the resulting bytes whereafter the Base64 characters /, + and = are been replaced by respectively ~, - and _ to make it URL-safe (so that no platform-sensitive URL-encoding needs to be done when used in URLs).
    
    Parameters:
    string - The string to be serialized.
    
    Returns:
    The serialized URL-safe string, or null when the given string is itself null.
    Since:
    
    1.2
  - unserializeURLSafe
```
public static String unserializeURLSafe(String string)
```
    Unserialize the given serialized URL-safe string. This does the reverse of serializeURLSafe(String).
    
    Parameters:
    string - The serialized URL-safe string to be unserialized.
    
    Returns:
    The unserialized string, or null when the given string is by itself null.
    
    Throws:
    
    IllegalArgumentException - When the given serialized URL-safe string is not in valid format as returned by serializeURLSafe(String).
    Since:
    
    1.2

Class Utils

Method Summary

Methods inherited from class java.lang.Object

Method Detail

isEmpty

isEmpty

isEmpty

isEmpty

coalesce

isOneOf

stream

close

unmodifiableSet

formatRFC1123

parseRFC1123

serializeURLSafe

unserializeURLSafe